Wireless Local Area Network (WLAN) is a basic service set in which two or more stations communicate directly with each other, e.g. by radio frequency signals. In a more common configuration, one or more “access points” are set up at predetermined locations and, each access point also has a wireless radio capability to permit wireless communications with nearby wireless-enabled devices such as desktop computers, notebooks, handheld devices, and the like. Each access point has a certain range and a wireless-enabled device must be within that range for effective communication to occur.
Most of the devices coupling to a wireless network are portable devices such as notebook computers, personal digital assistants (PDAs), and the like. These portable devices include a WLAN transceiver for communication. In addition, such portable devices are usually battery-powered. A WLAN transceiver includes a transmitter and a WLAN receiver. Power consumption is a key care about for WLAN receivers integrated on the portable devices.
The time between battery recharges of a portable device has a major impact on a user's experience. A WLAN or IEEE 802.11 standard compatible receivers spend a large proportion of power in listen mode. In listen mode, the WLAN receiver functions to determine presence of a data packet. This results in significant battery power consumption by the WLAN receiver, thus reducing battery life.